Power saving system for underwater vehicles

ABSTRACT

A power saving system for underwater vehicles includes a control system, a power unit and a battery. The control system controls the power unit to drive the underwater vehicle, and generates an output driving value. The control system includes a calculation unit, a three-axis accelerometer and gyro and an underwater vehicle weight value. The calculation unit creates a correspondent acceleration value by the output driving value and the underwater vehicle weight value. The three-axis accelerometer and gyro detects the acceleration of the underwater vehicle by every less than 0.5 second interval, and generates an acceleration value. The control system compares the correspondent acceleration value and the acceleration value to control the output driving value so as to save battery power and elongate the range of travelling of the underwater vehicles.

BACKGROUND OF THE INVENTION 1. Fields of the Invention

The present invention relates to an underwater vehicle, and more particularly, to a power saving system for an underwater vehicle so as to control the output of the driving unit according to resistance.

2. Descriptions of Related Art

The underwater vehicles are used widely for more and more tasks with roles and missions constantly evolving. For example, the oil and gas industry uses underwater vehicles to make detailed maps of the seafloor before they start building subsea infrastructure, pipelines and sub-sea completions can be installed in the most cost effective manner with minimum disruption to the environment. The underwater vehicles may have two types, one of which is autonomous underwater vehicles (AUVs), and the other is remotely operated underwater vehicles (ROVs). The AUVs allow the users to conduct precise surveys of areas where traditional bathymetric surveys would be less effective or too costly.

The underwater vehicles are detected and positioned by emitting sound waves from a sound emitting device to the underwater vehicles, and the underwater vehicles receive the sound waves and calculate the distance and direction between the device emitting the sound waves and the underwater vehicles, and the underwater vehicles send correspondent signals back to the device to calculate the position of the underwater vehicles.

Most of the underwater vehicles are powered by batteries which drive the motor and the propeller. The range of the underwater vehicles is limited based on the power from the batteries. Generally, the range of the underwater vehicles is about 8 hours. The underwater vehicles spend a lot of time on the travel of forth and back, and in some situations, the underwater vehicles may be brought away the route by strong current. Therefore, how to maintain the maximum battery power becomes a crucial concern.

The present invention intends to provide a power saving system for underwater vehicles to optimally use the battery power and to keep the underwater vehicles in action as long as possible.

SUMMARY OF THE INVENTION

The present invention relates to a power saving system for underwater vehicles, and comprises an underwater vehicle that includes a control system, a power unit and a battery, wherein the battery provides electric power to the power unit. The control system controls the power unit to drive the underwater vehicle, and generates an output driving value. The control system includes a calculation unit, a three-axis accelerometer and gyro and an underwater vehicle weight value that is built in the control system. The calculation unit creates a correspondent acceleration value by the output driving value and the underwater vehicle weight value. The three-axis accelerometer and gyro detects the acceleration of the underwater vehicle at interval of less than 0.5 second, and generates an acceleration value. The control system compares the correspondent acceleration value and the acceleration value.

When the correspondent acceleration value is larger than the acceleration value, the control system judges that the resistance applied to the underwater vehicle increases, and the output driving value is then increased. When the correspondent acceleration value is smaller than the acceleration value, the control system judges that the resistance applied to the underwater vehicle reduces, and the output driving value is then reduced.

Preferably, the power unit includes a propeller and a variable frequency motor which drives the propeller.

Preferably, the output driving value is an output force generated from the propeller to drive the underwater vehicle by the variable frequency motor.

Preferably, the control system includes a timer which is used to set the intervals and to calculate the intervals.

Preferably, the battery is a rechargeable battery.

The primary object of the present invention is to provide a power saving system for underwater vehicles, wherein the present invention calculates the speed of the underwater vehicle and the resistance applied to the underwater vehicle so as to control the output of the driving unit to save battery power.

The present invention will become more apparent from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the underwater vehicle and the components in the underwater vehicle of the present invention;

FIG. 2 shows the power saving system of the present invention, and

FIG. 3 shows the movement of the underwater vehicle of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 1 and 2, the power saving system for underwater vehicles of the present invention comprises an underwater vehicle 1 which is electrically connected with a control system 10, a power unit 20 and a battery 30. The battery 30 provides electric power to the power unit 20. The control system 10 controls the power unit 20 to drive the underwater vehicle 1 and generates an output driving value 11.

The control system 10 includes a calculation unit 12, a three-axis accelerometer and gyro 13 and an underwater vehicle weight value 14 which is built in the control system 10. The calculation unit 12 creates a correspondent acceleration value “A” by the output driving value 11 and the underwater vehicle weight value 14. The three-axis accelerometer and gyro 13 detecting the acceleration of the underwater vehicle 1 at interval of less than 0.5 second, and generates an acceleration value “a”. The control system 10 compares the correspondent acceleration value “A” and the acceleration value “a”. When the correspondent acceleration value “A” is larger than the acceleration value “a”, the control system 10 judges that the resistance applied to the underwater vehicle 1 increases, and the output driving value 11 is increased to overcome the resistance. On the contrary, when the correspondent acceleration value “A” is smaller than the acceleration value “a”, the control system 10 judges that the resistance applied to the underwater vehicle 1 reduces, and the output driving value 11 is reduced.

The control system 10 includes a timer (not shown) which is used to set the intervals and to calculate the intervals. Furthermore, the battery 30 is a rechargeable battery.

The power unit 20 includes a propeller 21 and a variable frequency motor (not shown) which drives the propeller 21. The output driving value 11 is the output force generated from the propeller 21 to drive the underwater vehicle 1 by the variable frequency motor.

According to the formula F=mA, wherein the “F” is the output driving value 11, and the “m” is the underwater vehicle weight value 14. The calculation unit 12 creates a correspondent acceleration value “A” by the output driving value 11 and the underwater vehicle weight value 14.

The three-axis accelerometer and gyro 13 detecting the acceleration of the underwater vehicle 1 at interval of less than 0.5 second, and generates an acceleration value “a”. As shown in FIG. 3, when the underwater vehicle 1 moves from the position represented by the dotted line to the position represented by the solid line, the three-axis accelerometer and gyro 13 generates an acceleration value “a”.

The control system 10 adjusts the output driving value 11 according to the comparison result between the correspondent acceleration value “A” and the acceleration value “a” to save the energy of the battery 30. In other words, because the three-axis accelerometer and gyro 13 detecting the acceleration of the underwater vehicle 1 at interval of less than 0.5 second, and generates an acceleration value “a”, so that the underwater vehicle 1 can be adjusted when necessary to prevent waste of the energy of the battery 30.

The adjustment to the output driving value 11 is able to use the battery 30 optimally so that the operation time of the underwater vehicle 1 can be prolonged. The mission of the underwater vehicle 1 can be completed by the effective use of the battery 30.

While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention. 

What is claimed is:
 1. A power saving system for underwater vehicles, comprising: an underwater vehicle having a control system, a power unit and a battery, the battery providing electric power to the power unit, the control system controlling the power unit to drive the underwater vehicle, and generating an output driving value, and the control system including a calculation unit, a three-axis accelerometer and gyro and an underwater vehicle weight value which is built in the control system, the calculation unit creating a correspondent acceleration value by the output driving value and the underwater vehicle weight value, the three-axis accelerometer and gyro detecting an acceleration of the underwater vehicle at interval of less than 0.5 second, and generating an acceleration value, the control system comparing the correspondent acceleration value and the acceleration value, when the correspondent acceleration value is larger than the acceleration value, the control system judges that an resistance applied to the underwater vehicle increases, and the output driving value is increased, when the correspondent acceleration value is smaller than the acceleration value, the control system judges that an resistance applied to the underwater vehicle reduces, and the output driving value is reduced.
 2. The power saving system for underwater vehicles as claimed in claim 1, wherein the power unit includes a propeller and a variable frequency motor which drives the propeller.
 3. The power saving system for underwater vehicles as claimed in claim 2, wherein the output driving value is an output force generated from the propeller to drive the underwater vehicle by the variable frequency motor.
 4. The power saving system for underwater vehicles as claimed in claim 1, wherein the control system includes a timer which is used to set the intervals and to calculate the intervals.
 5. The power saving system for underwater vehicles as claimed in claim 1, wherein the battery is a rechargeable battery. 